冲击荷载下圆柱型动力锂离子电池的响应特性研究

Study on the response characteristics of cylindrical power lithium-ion batteries under impact load

随着新能源汽车行业的快速发展,动力锂离子电池作为新能源汽车的核心部件之一,其安全性受到广泛关注,研究冲击荷载下动力锂离子电池的力学响应特性和热失控特性是有效防控新能源汽车发生碰撞导致火灾事故的关键。本工作选取21700圆柱型动力锂离子电池作为研究对象,通过自行搭建的电池撞击实验平台研究电池在平面撞击和圆柱面撞击下的安全性能,并记录锂离子电池的温度、电压和冲击荷载等表征数据,分析撞击高度、电池SOC对锂离子电池力学响应特性及热失控行为特征的影响。结果表明,随着电池SOC的增长,电池的抗冲击能力得到了提升;对于平面撞击实验,可认为电池的极限应变为-0.206,极限冲击应力为13.49MPa,对于圆柱面撞击实验,可认为电池的极限应变为-0.253,极限冲击应力为33.58 MPa;电池热失控的剧烈程度与落锤形状、撞击高度及电池自身荷电状态明显相关,圆柱面撞击对电池造成的破坏性更强,随着撞击高度和电池SOC的增加,电池热失控反应越剧烈,本研究为电池的安全性设计和新能源汽车火灾防控提供有效的数据支撑。

With the rapid development of the new energy vehicle industry,the safety of power lithium-ion batteries—one of the core components of these vehicles—has garnered significant attention.Understanding the mechanical response and thermal runaway characteristics of lithium-ion batteries under impact load is critical for effectively preventing and managing fire accidents resulting from collisions in new energy vehicles.This article investigates the safety performance of 21700 cylindrical lithium-ion batteries under planar and cylindrical impacts using a custom-built battery impact experimental platform.The study records data on temperature,voltage,and impact load,analyzing how impact height and state of charge(SOC)influence the mechanical response and thermal runaway behavior of the batteries.The results indicate that as SOC of the battery increases,its impact resistance improves;In planar impact experiments,the ultimate strain of the battery is-0.206,and the ultimate impact stress is 13.49 MPa.In cylindrical impact experiments,the ultimate strain of the battery is-0.253,and the ultimate impact stress is 33.58 MPa.The severity of battery thermal runaway is significantly influenced by the shape of the impactor,the impact height,and the battery's SOC.Cylindrical impacts cause more severe damage to the battery,and both increased impact height and higher battery SOC exacerbate the thermal runaway reaction.This study provides valuable data to support the safety design of batteries and the development of fire prevention and control measures for new energy vehicles.